This invention relates to the production of vinylidene chloride, specifically to dehydrohalogenation of 1,1,2-trichloroethane to produce vinylidene chloride.
Vinylidene chloride is commonly produced by dehydrohalogenation of 1,1,2- trichloroethane using inorganic bases such as calcium hydroxide or sodium hydroxide. The reaction, however, produces large quantities of a corresponding salt, e.g. calcium chloride or sodium chloride.
Thermal and catalytic cracking of 1,1,2-trichloroethane in also known to produce vinylidene chloride. These processes, however, produce undesirable quantities of by-products.
Use of certain amines, quaternary ammonium chloride salts of amines and hydrochloric acid salts of amines having a basic dissociation constant (pK.sub.b) less than 7 in the dehydrohalogenation of 1,1,2-trichloroethane is disclosed in U.S. Pat. No. 2,989,570. The process is said to exhibit selectivity for vinylidene chloride over by-products, but conversion of 1,1,2-trichloroethane has been found to be low.
It would be desirable to have a process having selectivity for vinylidene chloride, but in which there is a high conversion of 1,1,2-trichloroethane without production of salt.